JP5882460B2 - Hydrophobized calcium carbonate particles - Google Patents

Description

  The present invention relates to a method for reducing pitch in an aqueous medium generated in a papermaking or pulping process, the use of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate to reduce the amount of pitch in the aqueous medium, and hydrophobicity. The present invention relates to composite materials comprising pulverized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate and hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate and pitch.

  In the paper industry, a variety of quality fibers from a variety of sources, such as a combination of groundwood, heat and chemical treatments, wood into fibers, are obtained by processing and refining. During this pulping process, the natural resin contained in the wood is released in the form of fine droplets in the production water. This wood resin is often called “pitch” and may be deposited on the surface of the papermaking machine. This wood resin may take time to clean the machine, resulting in costly downtime for machinery. Is generated. Further, such deposits may appear as visible spots from yellow to black on the final paper product, or may lead to rolls of paper that affect product loss and paper quality degradation.

  Pitch formation can be described conceptually as occurring by three main mechanisms. The path through the first mechanism is the formation of an organic material film, which may be transparent or translucent. The thickness of the membrane varies with the concentration of the membrane, and a nucleus is required for the membrane to form the initial adhesion. This type of pitch is called film-like as suggested by the formation mechanism of the pitch. The second type of pitch is a pitch that can condense into small spheres with a diameter of 0.1 to 1.0 μm and is therefore referred to as a spherical pitch. A third commonly occurring pitch formation is agglomeration or pitch ball type and is often found in systems with the greatest problems with pitch deposit. The formed ball has a diameter of 1 to 120 μm. In the filmy or spherical state, pitch generally does not cause problems, but once aggregates are formed, pitch deposition then begins to occur. Such pitch deposits can be problematic in contaminants, recycling or secondary fiberization processes where adhesives, inks, hot melts, latexes and waxes aggregate to form deposits in papermaking equipment.

  Several attempts have been made in the art to control pitch deposits in the papermaking process. In this regard, one strategy involves introducing various inorganic forms of absorbent material, such as talc, bentonite or diatomaceous silica, into the papermaking process that absorb the pitch in the form of small droplets.

  For example, JP2004-292998A relates to talc used as a pitch adsorbent. WO 03/085199 A2 relates to a deposit control system comprising an inorganic or organic coagulant and particulate material for pulp containing white pitch / sticky, for example bentonite, clay, cross-linked polymer, colloidal silica, polysilicate, US 2003/0096143 A1. Describes a method for treating talc particles that improves the wettability of talc and / or the affinity of talc for cellulosic fibers. JP60665892A describes a pitch adsorbent composed of a magnesium-modified smectite clay mineral produced by modifying the surface layer of a smectite clay mineral with magnesium. FR 2900410 and FR 2900411 describe the treatment of mineral and / or talc amphoteric polymers used for pitch control. CA2, 205, 277 is effective for adding pitch, ink and sticky control in an effective amount of talc to the fiber suspension in contact with the paper machine and related parts and for pitch, ink and sticky control Describes a method for minimizing the stickiness of pitch, ink, and fine deposits in the papermaking process by adding such particles to the fiber, including adding a significant amount of bentonite to the suspension.

  This strategy has the advantage that the pitch is removed in the final product and therefore cannot accumulate further in the water circuit of the papermaking apparatus. In particular, talc is widely accepted as a very effective control agent for pitch deposits. However, the effect of talc in pitch control has not been strictly established. As talc reduces the stickiness of the pitch-like material or sticky, it is assumed that aggregates or deposits are less likely to form on the papermaking machine or to spot on the final paper product. Also, since the function of talc is to reduce the stickiness of the already deposited material, the rate at which the sticky material further accumulates on such surfaces is reduced. Here, it is important to add sufficient talc so that the overall tackiness of the surface of the system is reduced.

  However, one problem with talc is that if not enough talc is used, talc tends to be only included in the deposits and aggregates of the sticky material. Furthermore, talc is known to lose some of talc's affinity for colloidal materials in neutral and alkaline papermaking processes.

  Another strategy involves colloidal stabilization of the pitch through the use of dispersants or surfactants. By utilizing this strategy, the concentration of pitch droplets in the water of the papermaking apparatus occurs. For example, EP0740014 describes a pitch control agent that may comprise a kandite clay (serpentine family) whose particles are coated with a homopolymer or copolymer containing melamine formaldehyde. US 5,626,720A is a method for controlling pitch in an aqueous system used in pulping or papermaking, wherein (a) an epihalohydrin, diepoxide or epihalohydrin or diepoxide precursor, in the system or in the pulping or papermaking apparatus ( b) an alkylamine having functional groups for two epihalohydrins and (c) a method comprising adding a water-soluble polymer derived from an amine having a functional group for epihalohydrins greater than 2 and not having a carbonyl group doing. JP 11043895A describes pitch inhibitors by using cationic compounds prepared by the reaction of alkylene diamines with epihalohydrins. WO 98/05819 A1 relates to a liquid composition for the control of pitch deposits in pulping and papermaking comprising (1) a cationic guar polymer and (2) an aqueous solution of isobutylene / maleic anhydride. EP0586755A1 is a method for controlling pitch deposits in a pulping or papermaking process, the composition comprising up to 1.0% by weight of papermaking fibers based on the dry fiber weight of the composition A method is described wherein a cationic polyelectrolyte is included which is a poly (diallyldi (hydrogen or lower alkyl) ammonium salt) having a number average molecular weight greater than 500,000. US 2011/0094695 A1 describes a method for controlling the deposition of organic contaminants from pulp and papermaking systems using water-soluble aminoplast ether copolymers. EP 1950342 A1 describes an aqueous emulsion comprising a dialkylamide and a nonionic surfactant. US 2004/0231816 A1 is a method for controlling pitch and sticky, comprising adding hydrophobically modified hydroxyethylcellulose (HMHEC) and a cationic polymer to a cellulose fiber slurry (pulp) or papermaking process or to a papermaking system As described, a higher degree of organic deposit control and pitch retention on paper fibers is obtained compared to control by individual components. US Pat. No. 6,153,049 describes an ethyleneamine compound or a mixture of the ethyleneamine compounds used in an effective amount to reduce or inhibit white pitch deposits on the papermaking apparatus during the process of recycling the coated paper. US 6,051,160A relates to a liquid composition for the control of pitch deposits in pulping and papermaking, comprising (1) a derivatized cationic guar and (2) an aqueous solution of styrene maleic anhydride.

  JP 2002-212897A describes a pitch disturbance inhibitor for papermaking comprising a polydiallyldimethylammonium salt having a molecular weight of 20,000-200,000 and an inorganic aluminum compound as active ingredients.

JP 2004-292998 A International Publication No. 2003/085199 US Patent Application Publication No. 2003/0096143 Japanese Patent Laid-Open No. 06-065892 French Patent Invention No. 2900410 Specification French Patent Invention No. 2900411 Canadian Patent 2,205,277 Specification European Patent No. 0740014 US Pat. No. 5,626,720 JP 11-043895 A International Publication No. 98/05819 European Patent No. 0586755 US Patent Application Publication No. 2011/0094695 European Patent No. 1950342 US Patent Application Publication No. 2004/0231816 US Pat. No. 6,153,049 US Pat. No. 6,051,160 JP 2002-212897 A

  However, this strategy is often problematic because changes in temperature, pH, or electrolyte concentration cause spots and agglomeration in the deposit and / or final paper product as a result of pitch droplets on the machine surface. This is because of the occurrence of

  Accordingly, there continues to be a need for alternative materials that provide better performance than existing adsorbents and that effectively reduce the pitch in aqueous media generated in the papermaking or pulping process.

This and other objects are solved by the subject matter of the present invention. According to a first aspect of the present invention there is provided a method for reducing the pitch in an aqueous medium generated in a papermaking or pulping process, the method comprising:
a) providing an aqueous medium comprising a pitch generated in a papermaking or pulping process;
b) providing ground calcium carbonate and / or precipitated calcium carbonate;
c) providing a hydrophobizing agent selected from aliphatic carboxylic acids having between 5 and 24 carbon atoms;
d) contacting the ground calcium carbonate and / or precipitated calcium carbonate of step b) with the hydrophobizing agent of step c) to obtain hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate; and e) step contacting the aqueous medium provided in a) with the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate obtained in step d).

  We have surprisingly obtained by the above method according to the present invention by the same method without contacting the aqueous medium with hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate (step e). It has been found that the amount of pitch contained in the aqueous medium is less than the amount of pitch contained in the corresponding aqueous medium. More precisely, we contact the aqueous medium with the defined hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate to determine the amount of pitch in the aqueous medium that occurs in the papermaking or pulping process. It was found that this can be reduced.

For the purposes of the present invention, it should be understood that the following terms have the following meanings:
In the sense of the present invention, “pitch” refers to an adhesive material that forms insoluble deposits in the pulping and papermaking processes. These tacky materials can originate from the wood from which the paper is made. Pitch components include dissolved and colloidal substances (DCS) and include four types of lipophilic components such as i) fats and fatty acids, ii) stearyl esters and sterols, iii) terpenoids and iv) fats Characterized by a wax composed of alcohol and ester. The chemical composition of the pitch depends on the growth due to the season in which the fiber source, for example, the wood variety and the sample is produced. These lipophilic pitch components can be stabilized by the presence of lignosulfonate and polysaccharide. When recycled paper is used in the papermaking process, the term includes all sticky materials that are soluble in organic solvents but insoluble in water, including for example inks or adhesive materials present in recycled paper. Is often used as a more general term. Deposit materials generated from recycled fibers are also called "sticky". However, for the purposes of the present invention, the term “pitch” refers to any synthetic or natural material that forms insoluble deposits in the papermaking process, not only from natural pitch particles derived from paper pulp, but also from recycled fibers. Adhesive materials are also included.

  “Ground calcium carbonate (GCC)” in the sense of the present invention is calcium carbonate obtained from natural sources such as limestone, marble or chalk or dolomite, eg wet using a cyclone or classifier And / or processed by processes such as grinding, sieving and / or fractionation by a dry process.

  “Precipitated calcium carbonate (PCC)” in the sense of the present invention is generally obtained by precipitation after the reaction of carbon dioxide with lime in an aqueous environment or by precipitation of calcium and carbonate ion sources in water. Is a synthetic material.

  An “aqueous medium” is in the sense of the present invention a liquid medium comprising water, insoluble solids such as fibers and pitch components.

  The term “aliphatic carboxylic acid” in the sense of the present invention refers to a linear, branched, saturated, unsaturated or alicyclic organic compound composed of carbon and hydrogen. The organic compound further contains a carboxyl group disposed at the end of the carbon skeleton.

  The terms “hydrophobized” ground calcium carbonate and / or “hydrophobized” precipitated calcium carbonate have been processed in the sense of the present invention by additional processing steps to make the surface of the calcium carbonate particles more hydrophobic. It refers to ground calcium carbonate and / or hydrophobized precipitated calcium carbonate.

Another aspect of the present invention is an aliphatic carboxylic acid having a specific surface area between 10% and 19% of ground and / or precipitated calcium carbonate having 5 to 24 carbon atoms and the reaction of said aliphatic carboxylic acid It relates to hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate which is covered by a coating consisting of the product. It is preferred that a specific surface area of between 10% and 19% of ground and / or precipitated calcium carbonate is covered by a coating consisting of stearic acid and the reaction product of stearic acid. Coating comprising an aliphatic carboxylic acid having a specific surface area of between 13 and 17% of ground and / or precipitated calcium carbonate having between 5 and 24 carbon atoms and a reaction product of said aliphatic carboxylic acid More preferably, it is preferably covered by a coating consisting of stearic acid and the reaction product of stearic acid. The ground calcium carbonate (GCC) source is selected from marble, chalk, calcite, dolomite, limestone and mixtures thereof, and / or precipitated calcium carbonate (PCC) is one of the aragonite, vaterite and / or calcite mineral crystal forms It is also preferable to select from the above. The ground calcium carbonate particles and / or precipitated calcium carbonate particles are measured according to the precipitation method, from 0.1 to 50 μm, preferably from 0.1 to 25 μm, more preferably from 0.1 to 15 μm, most preferably from 0.1. More preferably, it has a weight median particle size d ₅₀ value of 5 to 5 μm. The ground calcium carbonate particles and / or precipitated calcium carbonate particles are 0.5 m ² / g to 25 m ² / g, preferably 0.5 m ² / g to 15 m ² / g, measured using nitrogen and BET methods. More preferably, it has a specific surface area of 1 m ² / g to 11 m ² / g. More preferably, the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate is in powder form and / or fine grain or slurry form.

  A further aspect of the invention relates to the use of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate that reduces the amount of pitch in the aqueous medium generated in the papermaking or pulping process. A still further aspect of the invention relates to a composite comprising hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate and pitch.

  According to a preferred embodiment of the method according to the invention, the ground calcium carbonate (GCC) source is selected from marble, chalk, calcite, dolomite, limestone and mixtures thereof and / or precipitated calcium carbonate (PCC) is aragonite, Selected from one or more of the vaterite and / or calcite mineral crystal forms.

  According to another preferred embodiment of the method according to the invention, the ground calcium carbonate and / or precipitated calcium carbonate is in powder form or slurry form.

According to another preferred embodiment of the method according to the invention, the ground calcium carbonate particles and / or precipitated calcium carbonate particles are measured according to the precipitation method, more preferably from 0.1 to 50 μm, preferably from 0.1 to 25 μm. Preferably it has a weight median particle size d ₅₀ value of 0.1 to 15 μm, most preferably 0.5 to 5 μm.

The preferred embodiment, ground calcium carbonate particles and / or precipitated calcium carbonate particles, as measured using nitrogen and the BET method, of 0.5 m ² / g of ^{25 m} 2 / g, preferably 0.5 m ² / The specific surface area is from g to 15 m ² / g, more preferably from 1 m ² / g to 11 m ² / g.

  According to another preferred embodiment of the method according to the invention, the hydrophobizing agent is pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid. , Palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, arachidic acid, heicosyl acid, behenic acid, triicosyl acid, lignoceric acid and mixtures thereof, preferably the hydrophobizing agent is octanoic acid, decanoic acid , Lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid and mixtures thereof, most preferably the hydrophobizing agent is a group consisting of myristic acid, palmitic acid, stearic acid and mixtures thereof More selected.

  According to yet another preferred embodiment, the hydrophobizing agent comprises a mixture of two aliphatic carboxylic acids having between 5 and 24 carbon atoms, where one aliphatic carboxylic acid is stearic acid.

  According to another preferred embodiment, one aliphatic carboxylic acid is stearic acid and the other is selected from the group consisting of octanoic acid, myristic acid, palmitic acid, arachidic acid, behenic acid and lignoceric acid.

  According to a preferred embodiment of the method according to the invention, step d) is performed by mixing ground calcium carbonate and / or precipitated calcium carbonate with a hydrophobizing agent.

  According to another preferred embodiment of the method according to the invention, both ground and / or precipitated calcium carbonate of step b) and the hydrophobizing agent of step c) are provided in the dry state or in a solvent, step d) is performed.

  According to yet another preferred embodiment of the method according to the invention, either ground calcium carbonate and / or precipitated calcium carbonate of step b) and the hydrophobizing agent of step c) are provided in a solvent, step d) comprising Done.

  According to a preferred embodiment of the method according to the invention, the contact of ground calcium carbonate and / or precipitated calcium carbonate with the hydrophobizing agent in step d) is carried out at an elevated temperature so that the hydrophobizing agent is in a liquid or molten state. Is called. Preferably, the contact in step d) is at a temperature of at least 50 ° C, preferably at least 75 ° C, more preferably between 50 ° C and 120 ° C, most preferably between 70 ° C and 100 ° C. Do.

  According to another preferred embodiment of the method according to the invention, the specific surface area of less than 20% of the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate obtained in step d) Covered by a coating of product.

  According to yet another preferred embodiment of the process according to the invention, the specific surface area between 10% and 19% of the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate obtained in step d), preferably from 13%. A specific surface area of between 17% is covered by a coating consisting of the hydrophobizing agent and the reaction product of the hydrophobizing agent.

  According to a preferred embodiment of the method according to the invention, the aqueous medium to be treated is 0.05 to 20% by weight, preferably 0.5 to 10% by weight, most preferably based on the total weight of the aqueous medium. Contacted with 0.1 to 5% by weight of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate.

  According to another preferred embodiment of the method according to the invention, the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate obtained in step d) is used in powder form and / or in fine-grained or slurry form.

  According to another preferred embodiment of the method according to the invention, the pH of the pitch-containing aqueous medium is greater than 6, more preferably 6.5, prior to the addition of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate. To a value greater than 7, still more preferably greater than 7.

  According to a preferred embodiment of the method according to the invention, the pitch-containing aqueous medium is used for mechanical pulps used in the papermaking process, for example groundwood, TMP (thermomechanical pulp) or chemithermomechanical pulp (CTMP) as well as chemical pulps, for example Selected from the group comprising kraft pulp or sulfate pulp or recycled pulp.

  As mentioned above, the method of the present invention for reducing the pitch in an aqueous medium generated in a papermaking or pulping process comprises steps a), b), c), d) and e). In the following, further details of the invention and in particular the above-mentioned steps of the method of the invention for reducing the pitch in the aqueous medium generated in the aqueous medium papermaking or pulping process are described.

Step a): Providing Aqueous Medium Containing Pitch According to step a) of the method of the present invention, an aqueous medium containing pitch generated in the papermaking or pulping process is provided.

  Pitch-containing aqueous media are mechanical pulps used in papermaking or pulping processes, such as groundwood, TMP (thermomechanical pulp), or chemithermomechanical pulp (CTMP) and chemical pulps, such as kraft pulp or sulfate pulp or recycled pulp It is understood that.

  “Mechanical pulp” is, in the sense of the present invention, prepared by crushing raw pulp and chips of pulpwood into their respective fiber components by mechanical energy. Pitch-containing pulps that can be subjected to the method of the invention are in particular obtained from wood pulp, which is the most common material used to make paper materials. “Crumbled wood” as used herein is generally obtained from softwood, such as spruce, pine, fir, larch, and hemlock, but also from some hardwood, such as eucalyptus, Produced by crushing into relatively short fibers.

  “Thermomechanical pulp”, as used herein, is manufactured in a thermomechanical process in which wood chips or sawdust are softened by steam before entering the pressure refiner.

  “Chemithermomechanical pulp”, as used herein, is produced by treating wood chips with chemicals such as sodium sulfite and steam followed by mechanical treatment.

  “Chemical pulp”, as used herein, is produced by treating wood chips or sawdust with chemicals to release cellulose fibers by removing binders, such as lignin resin and gum. Sulfate or kraft is two types of chemical pulping, and kraft is the main pulping process in chemical pulping.

  “Recycled pulp” as used herein is obtained from recycled paper and paperboard or waste paper.

  Pitch can be reduced by the present invention and can be described as dissolved colloidal material (DCS), including types such as fats and fatty acids, steryl esters and sterols, terpenoids and waxes consisting of fatty alcohols and esters . The chemical composition of the pitch depends on the fiber source, such as the type of tree, and the growth due to the season in which the sample is manufactured.

  It should be noted that with respect to recycled pulp, the term pitch is also used to describe the sticky, hydrophobic and / or surface charged, flexible organic materials found in recycled paper systems. These organic materials include a wide variety of different materials such as adhesives, styrene-butadiene binders, latex in general, rubber, vinyl acrylate, polyisoprene, polybutadiene, hot melt, and the like.

  Optionally, additives can be added to the pitch-containing aqueous medium sample to be treated. Examples of the additive include a pH adjuster.

Step b): ground calcium carbonate and / or precipitated calcium carbonate Step b) of the method of the present invention provides ground calcium carbonate and / or precipitated calcium carbonate.

  It is understood that ground (or natural) calcium carbonate (GCC) is a natural form of calcium carbonate mined from sedimentary rocks such as limestone or chalk or from modified marble. Calcium carbonate is known to exist as three crystalline polymorphs: calcite, aragonite, and vaterite. Calcite is the most common crystal polymorph and is considered the most stable crystal form of calcium carbonate. Aragonite, although less common, has a discontinuous or clustered acicular orthorhombic crystal structure. Vaterite is the rarest calcium carbonate polymorph and is generally unstable. The ground calcium carbonate is said to be a trigonal system-rhombohedral system, and is substantially composed of a calcite polymorph corresponding to the most stable polymorph among the calcium carbonate polymorphs.

  Preferably, the ground calcium carbonate source is selected from the group comprising marble, chalk, calcite, dolomite, limestone and mixtures thereof. In a preferred embodiment, the ground calcium carbonate source is calcite.

  The term calcium carbonate “source” in the sense of the present application refers to a natural mineral material from which calcium carbonate is obtained. The calcium carbonate source may further include natural components such as magnesium carbonate, aluminosilicate and the like.

  In addition or alternatively, precipitated calcium carbonate (PCC) is provided. PCC-type calcium carbonate polymorphs are less stable, in addition to calcite, of aragonite type with orthorhombic needle-like crystal shape and hexagonal vaterite type which is still less stable than aragonite Often includes polymorphs. Different PCC forms can be identified according to these characteristic x-ray powder diffraction (XRD) peaks. PCC synthesis occurs most commonly by a synthetic precipitation reaction that involves contacting carbon dioxide with a solution of calcium hydroxide, which is provided during the formation of an aqueous suspension of calcium oxide, also known as quicklime. Most often, calcium hydroxide suspensions are commonly known as lime milk. Depending on the reaction conditions, this PCC may appear in a variety of forms, including both stable and unstable polymorphs. In fact, PCC is often a thermodynamically unstable calcium carbonate material. When referred to in the context of the present invention, PCC is a synthetic carbonate obtained by carbonation of a slurry of calcium hydroxide, commonly referred to in the art as a lime slurry or lime milk when obtained from finely divided calcium oxide particles in water. It shall be understood to mean a calcium product.

  Preferred synthetic calcium carbonate is precipitated calcium carbonate comprising aragonite, vaterite or calcite mineral crystal form or mixtures thereof.

  In a preferred embodiment, ground calcium carbonate is provided.

In a particularly preferred embodiment, the ground calcium carbonate and / or precipitated calcium carbonate provided in step b) of the process is not surface-reacted ground calcium carbonate and / or surface-reacted precipitated calcium carbonate. In particular, the ground calcium carbonate and / or precipitated calcium carbonate provided in step b) has not been treated with acid and with carbon dioxide prior to step d) of the process in the sense of the present invention. Furthermore, the ground calcium carbonate and / or precipitated calcium carbonate is measured according to the precipitation method, from 0.1 to 50 μm, preferably from 0.1 to 25 μm, more preferably from 0.1 to 15 μm, most preferably from 0.1. It is preferred to have a weight median particle size d ₅₀ value of 5 to 5 μm. For example, ground calcium carbonate particles and / or precipitated calcium carbonate particles have a weight median particle size d ₅₀ value of 1.5 μm.

The ground calcium carbonate particles and / or precipitated calcium carbonate particles are 0.5 m ² / g to 25 m ² / g, preferably 0.5 m ² / g to 15 m ² / g, measured using nitrogen and BET methods. More preferably, it has a specific surface area of 1 m ² / g to 11 m ² / g. For example, ground calcium carbonate particles and / or precipitated calcium carbonate particles have a specific surface area of 3.5 m ² / g to 4 m ² / g. Alternatively, the ground calcium carbonate particles and / or precipitated calcium carbonate particles have a specific surface area of 1.0 m ² / g to 1.5 m ² / g. Alternatively, the ground calcium carbonate particles and / or the precipitated calcium carbonate particles have a specific surface area of 10 m ² / g to 10.5 m ² / g.

In a preferred embodiment, the ground natural calcium carbonate particles and / or precipitated calcium carbonate particles have a specific surface area in the range of 0.5 m ² / g to 25 m ² / g and a weight median particle size in the range of 0.1 to 50 μm. d has a value of ₅₀ . More preferably, the specific surface area is in the range of 0.5 m ² / g to 15 m ² / g and the weight median particle size d ₅₀ value is in the range of 0.1 to 25 μm. Even more preferably, the specific surface area is in the range of 0.5 m ² / g to 15 m ² / g and the weight median particle size is in the range of 0.1 to 15 μm. Most preferably, the specific surface area is in the range of 1 m ² / g to 11 m ² / g and the weight median particle size d ₅₀ value is in the range of 0.5 to 5 μm. For example, ground calcium carbonate particles and / or precipitated calcium carbonate particles have a specific surface area in the range of 3.5 m ² / g to 4 m ² / g and a weight median particle size d ₅₀ value of 1.5 μm. Alternatively, the ground calcium carbonate particles and / or precipitated calcium carbonate particles have a specific surface area in the range of 10 m ² / g to 10.5 m ² / g and a weight median particle size d ₅₀ of 0.6 μm.

In one particularly preferred embodiment, ground calcium carbonate particles are provided having a specific surface area in the range of 3.5 m ² / g to 4 m ² / g and a weight median particle size d ₅₀ value of 1.5 μm. In another particularly preferred embodiment, ground calcium carbonate particles having a specific surface area in the range of 10 m ² / g to 10.5 m ² / g and a weight median particle size d ₅₀ value of 0.6 μm are provided.

  In a preferred embodiment, the ground calcium carbonate and / or precipitated calcium carbonate is provided in the form of a powder.

The term “powder” as used in the present invention comprises at least 90% by weight of a solid mineral powder of inorganic mineral matter, based on the total weight of the powder, the particles measured according to the sedimentation method, less than 50 μm Preferably having a weight median particle size d ₅₀ value of less than 25 μm, more preferably less than 15 μm, most preferably between 0.5 μm and 5.0 μm.

  Alternatively or additionally, the ground calcium carbonate and / or precipitated calcium carbonate is provided in the form of a slurry.

  “Slurry” in the sense of the present invention is a suspension comprising insoluble solids and water and optionally further additives. The slurry usually contains a large amount of solids and is more viscous and generally denser than the liquid from which the slurry is formed. In the art, the general term “dispersion” specifically includes “suspension” as a particular type of dispersion.

  In order to obtain each size of ground calcium carbonate particles and / or precipitated calcium carbonate, the ground calcium carbonate and / or precipitated calcium carbonate is ground before treatment with a hydrophobizing agent according to step d) of the process of the invention. A process may be applied. The grinding step can be performed by any conventional grinding device known to those skilled in the art, for example by a grinding mill.

  Such a grinding step may require drying the ground calcium carbonate and / or precipitated calcium carbonate, thereby obtaining ground calcium carbonate and / or precipitated calcium carbonate in the form of a powder.

  The term “dried” refers to less than 0.5 wt%, preferably less than 0.2 wt%, more preferably 0.1 wt%, based on the total weight of ground and / or precipitated calcium carbonate particles. Refers to ground calcium carbonate particles and / or precipitated calcium carbonate particles having a total surface moisture content of less than% by weight.

Step c): Providing a Hydrophobizing Agent Step c) of the method of the present invention provides a hydrophobizing agent selected from aliphatic carboxylic acids having between 5 and 24 carbon atoms.

  The aliphatic carboxylic acid may be selected in the sense of the present invention from one or more linear, branched, saturated, unsaturated and / or alicyclic carboxylic acids. Preferably, the aliphatic carboxylic acid is a monocarboxylic acid, i.e. the aliphatic carboxylic acid is characterized in that a single carboxyl group is present. The carboxyl group is located at the end of the carbon skeleton.

  In a preferred embodiment, the hydrophobizing agent is selected from saturated unbranched carboxylic acids, ie the hydrophobizing agent is preferably pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid. Selected from the group of carboxylic acids consisting of acids, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, arachidic acid, heicosyl acid, behenic acid, triicosyl acid, lignoceric acid and mixtures thereof The

  In a further preferred embodiment, the hydrophobizing agent is selected from the group consisting of octanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid and mixtures thereof. Preferably, the hydrophobizing agent is selected from the group consisting of myristic acid, palmitic acid, stearic acid and mixtures thereof.

  In an especially preferred embodiment, the hydrophobizing agent is stearic acid.

  In one preferred embodiment, the hydrophobizing agent comprises a mixture of at least two aliphatic carboxylic acids having between 5 and 24 carbon atoms. Preferably, a mixture of two carboxylic acids having between 5 and 24 carbon atoms is provided, provided that one aliphatic carboxylic acid is stearic acid.

  In an even more preferred embodiment, one aliphatic carboxylic acid is from an acid and the other aliphatic carboxylic acid is selected from the group consisting of octanoic acid, myristic acid, palmitic acid, arachidic acid, behenic acid and lignoceric acid. The

  When the hydrophobizing agent according to the present invention comprises a mixture of two aliphatic carboxylic acids having between 5 and 24 carbon atoms, the molar ratio of stearic acid and second aliphatic carboxylic acid is from 99: 1. 1:99, more preferably 50: 1 to 1:50, even more preferably 25: 1 to 1:25, most preferably 10: 1 to 1:10. In one particularly preferred embodiment of the invention, the molar ratio of stearic acid to the second aliphatic carboxylic acid is from 90: 1 to 1: 1, more preferably from 90: 1 to 10: 1, most preferably 90: 1. To 50: 1. In another preferred embodiment, the molar ratio of stearic acid to the second aliphatic carboxylic acid is 1: 1.

  When the hydrophobizing agent according to the invention comprises a mixture of two aliphatic carboxylic acids having between 5 and 24 carbon atoms, the hydrophobizing agent preferably comprises a mixture of stearic acid and myristic acid. In a further preferred embodiment, the hydrophobizing agent comprises a mixture of stearic acid and palmitic acid. In yet another preferred embodiment, the hydrophobizing agent comprises a mixture of stearic acid and arachidic acid. In yet another preferred embodiment, the hydrophobizing agent comprises a mixture of stearic acid and behenic acid. In a further preferred embodiment, the hydrophobizing agent comprises a mixture of stearic acid and lignoceric acid. In another preferred embodiment, the hydrophobizing agent comprises a mixture of stearic acid and octanoic acid.

  The hydrophobizing agent is preferably provided in the form of flakes of each aliphatic carboxylic acid. In addition or alternatively, the hydrophobizing agent is provided in a solvent, i.e. the hydrophobizing agent is in solution. The “dissolved state” is defined in the meaning of the present invention as a state in which the hydrophobizing agent and the solvent form a homogeneous phase.

  Preferably, the solvent is selected from the group of alcohols, ketones, carboxy ethers, ethers, alkanes or aryl compounds. The solvent preferably has a melting point between -90 ° C and 0 ° C. For example, ethanol, acetone or toluene can be selected.

  In a preferred embodiment, the hydrophobizing agent is provided in the liquid or molten state of each aliphatic carboxylic acid, ie, when the aliphatic carboxylic acid is a solid at room temperature, the hydrophobizing agent is a liquid of the aliphatic carboxylic acid. It is heated to such a temperature that a shape is obtained. Preferably, the hydrophobizing agent is heated to a temperature of at least 50 ° C, preferably at least 75 ° C, more preferably from 50 ° C to 120 ° C, most preferably from 70 ° C to 100 ° C. For example, the hydrophobizing agent is heated to a temperature of 80 ° C.

Step d): Contacting ground calcium carbonate and / or precipitated calcium carbonate with a hydrophobizing agent According to step d) of the process according to the invention, in order to obtain hydrophobized ground calcium carbonate and / or hydrophobized ground calcium carbonate, step b) ) Ground calcium carbonate and / or precipitated calcium carbonate is contacted with the hydrophobizing agent of step c).

  In the process of the present invention, the contact of ground calcium carbonate and / or precipitated calcium carbonate with a hydrophobizing agent is preferably carried out by mixing ground calcium carbonate and / or precipitated calcium carbonate with a hydrophobizing agent. “Mixing” in the sense of the present invention can be carried out by any conventional mixing process known to the person skilled in the art. Preferably, the mixing is performed under continuous stirring in order to bring the ground calcium carbonate particles and / or precipitated calcium carbonate particles of step b) into uniform contact with the hydrophobizing agent of step c).

  In a preferred embodiment, either the ground calcium carbonate and / or precipitated calcium carbonate of step b) or the hydrophobizing agent of step c) is provided in a solvent and the contacting of step d) is performed. That is, either the ground calcium carbonate and / or precipitated calcium carbonate of step b) is provided in the form of a slurry, or the hydrophobizing agent of step c) is dissolved in a solvent. For example, if the ground calcium carbonate and / or precipitated calcium carbonate of step b) is provided in the form of a slurry, the hydrophobizing agent of step c) is provided in the form of flakes, or the hydrophobizing agent of step c) Is provided in a liquid or molten state. Alternatively, if the hydrophobizing agent of step c) is provided in a solvent, the ground and / or precipitated calcium carbonate of step b) is provided in powder form.

  In a preferred embodiment, the ground and / or precipitated calcium carbonate of step b) is provided in the form of a slurry and the hydrophobizing agent of step c) is provided in the molten state. In a preferred embodiment, the ground calcium carbonate and / or precipitated calcium carbonate slurry is preheated.

  In another preferred embodiment, the contacting of step d) comprises both the ground calcium carbonate and / or precipitated calcium carbonate of step b) and the hydrophobizing agent of step c) (i) in the dry state or (ii) in a solvent. It can be done by contacting with either.

  For example, if the contact of step d) is carried out in a solvent, then the hydrophobizing agent of step c) needs to be dissolved in the solvent, but the ground calcium carbonate and / or precipitated calcium carbonate of step b) Provided in slurry form. In a preferred embodiment, the ground calcium carbonate and / or precipitated calcium carbonate slurry is preheated.

  Alternatively, the contacting in step d) is performed by contacting the ground calcium carbonate and / or precipitated calcium carbonate in step b) and the hydrophobizing agent in step c) in a dry state. For example, the ground calcium carbonate and / or precipitated calcium carbonate of step b) is provided in powder form, the hydrophobizing agent of step c) is provided in the form of flakes, or the hydrophobizing agent of step c) is liquid or molten The contact of step d) provided in the state is performed. In a preferred embodiment, the ground and / or precipitated calcium carbonate of step b) is provided in powder form and the hydrophobizing agent of step c) is provided in the molten state.

  In a preferred embodiment of this step, the contact between the ground calcium carbonate and / or precipitated calcium carbonate and the hydrophobizing agent is performed at an elevated temperature so that the hydrophobizing agent is in a liquid or molten state.

  “Liquid” or “molten state” is defined in the sense of the present invention as a state in which the hydrophobizing agent is completely liquid, in other words completely melted. The melting phenomenon occurs at a constant temperature when energy is applied, but is observed in a curve plotting the energy input obtained by temperature and Dynamic Scanning Calorimetry (DSC) (DIN 51005: 1983-11). As such, the material is said to have melted at a point after melting when the temperature starts to rise.

  Preferably, the ground calcium carbonate and / or precipitated calcium carbonate provides the hydrophobizing agent to at least 50 ° C, preferably at least 75 ° C, more preferably between 50 ° C and 120 ° C, most preferably 70 ° C to 100 ° C. Is contacted at a temperature between. In a preferred embodiment, the ground calcium carbonate and / or precipitated calcium carbonate is contacted with the hydrophobizing agent at a temperature of 80 ° C. In particularly preferred embodiments, the ground calcium carbonate and / or precipitated calcium carbonate is contacted with the hydrophobizing agent at a constant temperature.

  For example, when stearic acid is used as the hydrophobizing agent, the ground calcium carbonate and / or precipitated calcium carbonate is contacted with the hydrophobizing agent, preferably at a temperature of at least 70 ° C, more preferably at a temperature of 80 ° C. . When octanoic acid or myristic acid is used as the hydrophobizing agent, the ground calcium carbonate and / or precipitated calcium carbonate contacts the hydrophobizing agent, preferably at a temperature of at least 55 ° C, more preferably at a temperature of 65 ° C. Is done. When palmitic acid is used as the hydrophobizing agent, the ground calcium carbonate and / or precipitated calcium carbonate is contacted with the hydrophobizing agent, preferably at a temperature of at least 65 ° C, more preferably at a temperature of 75 ° C. When arachidic acid is used as the hydrophobizing agent, the ground calcium carbonate and / or precipitated calcium carbonate is contacted with the hydrophobizing agent, preferably at a temperature of at least 75 ° C, more preferably at a temperature of 85 ° C. When behenic acid is used as the hydrophobizing agent, the ground calcium carbonate and / or precipitated calcium carbonate is contacted with the hydrophobizing agent, preferably at a temperature of at least 80 ° C, more preferably at a temperature of 90 ° C. When lignoceric acid is used as the hydrophobizing agent, the ground calcium carbonate and / or precipitated calcium carbonate is contacted with the hydrophobizing agent, preferably at a temperature of at least 85 ° C, more preferably at a temperature of 95 ° C.

  In a preferred embodiment, the hydrophobized ground calcium carbonate is prepared by contacting the ground calcium carbonate with stearic acid at a temperature of 80 ° C.

  In another preferred embodiment, the hydrophobized precipitated calcium carbonate is prepared by contacting the precipitated calcium carbonate with stearic acid at a temperature of 80 ° C.

  In a further preferred embodiment, the ground calcium carbonate and / or precipitated calcium carbonate is preheated, i.e. the powder or slurry of ground calcium carbonate and / or precipitated calcium carbonate is distributed in order to evenly distribute the heat in the particles or in the slurry. Stir at high temperature for a sufficient period of time.

  Preferably, the preheating of the ground calcium carbonate particles and / or precipitated calcium carbonate particles is carried out with stirring at an elevated temperature. In a preferred embodiment, the preheating of the ground calcium carbonate and / or precipitated calcium carbonate is at least 50 ° C, preferably at least 75 ° C, more preferably between 50 ° C and 120 ° C, most preferably 70 ° C to 100 ° C. It is carried out under continuous stirring at a constant temperature between 0 ° C. In a further preferred embodiment, the preheating of the ground calcium carbonate and / or precipitated calcium carbonate takes place under continuous stirring at a constant temperature of 80 ° C.

  When ground calcium carbonate and / or precipitated calcium carbonate is preheated, preheating is preferably performed over a period of at least 30 seconds, more preferably at least 90 seconds, and most preferably at least 120 seconds. In a preferred embodiment, the preheating is performed over a period of between 1 and 5 minutes, preferably between 1 and 4 minutes, most preferably between 2 and 3 minutes, for example over 2.5 minutes. For example, the preheating of ground calcium carbonate and / or precipitated calcium carbonate is performed over a period of 2.5 minutes under continuous stirring at a constant temperature of 80 ° C.

  After the hydrophobizing agent is added to the ground calcium carbonate and / or precipitated calcium carbonate, the hydrophobizing agent and ground carbonic acid are distributed in order to uniformly distribute the hydrophobizing agent on the surface of the ground calcium carbonate particles and / or the precipitated calcium carbonate particles. A blend of calcium and / or precipitated calcium carbonate is contacted, preferably by mixing at a high temperature for a sufficient period of time. In a preferred embodiment, the hydrophobizing agent and the blend of ground calcium carbonate and / or precipitated calcium carbonate is at least 50 ° C, preferably at least 75 ° C, more preferably between 50 ° C and 120 ° C, most preferably Are mixed at a temperature between 70 ° C and 100 ° C. For example, a hydrophobizing agent and a blend of ground calcium carbonate and / or precipitated calcium carbonate are mixed at a temperature of 80 ° C.

  Mixing of the hydrophobizing agent and milled calcium carbonate and / or precipitated calcium carbonate blend at elevated temperature is preferably carried out over a period of at least 1 minute, more preferably at least 2 minutes, and most preferably at least 4 minutes.

  Mixing of the hydrophobizing agent and the blend of ground calcium carbonate and / or precipitated calcium carbonate at high temperature occurs during one or more intervals. The term “single interval” as used herein refers to continuous mixing of a formulation over a predetermined period of time at an elevated temperature. The term “more interval” refers to discontinuous mixing of the formulation at a high temperature over a predetermined period of time when mixing is interrupted at least once.

  In a preferred embodiment, the mixing of the hydrophobizing agent and the blend of ground calcium carbonate and / or precipitated calcium carbonate at a high temperature occurs during a single interval. For example, the hydrophobizing agent and ground calcium carbonate and / or precipitated calcium carbonate formulation may be between 1 and 10 minutes, preferably between 2 and 8 minutes, most preferably between 4 and 6 minutes, for example Mix continuously over a period of 5 minutes. For example, the contacting of the hydrophobizing agent and the blend of ground calcium carbonate and / or precipitated calcium carbonate is carried out for 5 minutes under continuous mixing at a temperature of 80 ° C.

  If mixing of the hydrophobizing agent and the blend of ground calcium carbonate and / or precipitated calcium carbonate at high temperature occurs in more than one interval, the mixing is preferably done in two intervals. In one preferred embodiment, the mixing of the hydrophobizing agent and the blend of ground calcium carbonate and / or precipitated calcium carbonate at elevated temperatures is performed in two equal intervals, for example, the intervals are approximately equal times. For example, hydrophobicity at high temperatures, each interval having an equal length between 1 and 5 minutes, preferably between 1 and 4 minutes, most preferably between 2 and 3 minutes, for example 2.5 minutes Mixing of the agent and a blend of ground calcium carbonate and / or precipitated calcium carbonate takes place.

  In another preferred embodiment, the mixing of the hydrophobizing agent and ground calcium carbonate blend at elevated temperature occurs in two unequal intervals, i.e., the time of the intervals is not equal. For example, hydrophobizing agents at high temperatures and ground calcium carbonate and / or having a length between 1 minute and 5 minutes, preferably between 1 minute and 4 minutes, most preferably between 2 minutes and 3 minutes. Alternatively, a blend of precipitated calcium carbonate is mixed.

The degree of hydrophobicity (X) can be adjusted by the percentage of available specific surface area covered by the coating consisting of the hydrophobizing agent and the reaction product of the hydrophobizing agent. The degree of hydrophobicity (X) can be calculated using Equation 1 below:
X = δm _Exp / (M _FA * A _s * n _A ) [1]
X: degree of hydrophobicity δ _mExp : experimental mass loss in TGA between 150 ° C. and 400 ° C. M _FA : molecular weight of carboxylic acid A _s : specific surface area of ground calcium carbonate particles and / or precipitated calcium carbonate particles n _A : Carboxylic acid molecules required to coat 1 m ² of ground calcium carbonate particles and / or precipitated calcium carbonate. Usually 6 μmol * m ⁻² for carboxylic acids.

  Preferably, the degree of hydrophobicity still allows the formation of a suspension of hydrophobized ground calcium carbonate particles and / or hydrophobized precipitated calcium carbonate particles in the aqueous medium to be treated under reasonable agitation. Adjusted to the value. Levitation of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate to the water surface should be avoided even under reasonable agitation.

  The term “reaction product”, in the sense of the present invention, contacts ground calcium carbonate and / or precipitated calcium carbonate with a hydrophobizing agent selected from aliphatic carboxylic acids having between 5 and 24 carbon atoms. Refers to the product usually obtained by Said reaction product is preferably formed between an applied hydrophobizing agent and molecules located on the surface of ground calcium carbonate and / or precipitated calcium carbonate.

  In particular, less than 20% of the specific surface area of the ground and / or precipitated calcium carbonate particles obtained in step d) is covered by a coating comprising a hydrophobizing agent and a reaction product of the hydrophobizing agent. In a preferred embodiment, the specific surface area between 10% and 19%, preferably between 13% and 17% of the ground and / or precipitated calcium carbonate particles obtained in step d) is hydrophobic. Coated with a coating consisting of the reaction product of an agent and a hydrophobizing agent. For example, 15% specific surface area of ground calcium carbonate particles and / or precipitated calcium carbonate particles is covered by a coating consisting of a hydrophobizing agent and a reaction product of the hydrophobizing agent. In a particularly preferred embodiment, 15% of the specific surface area of the ground calcium carbonate particles and / or precipitated calcium carbonate particles is covered by a coating consisting of stearic acid and a reaction product of stearic acid.

  The hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate thus obtained is advantageously realized in step e) of the method of the present application in order to reduce the pitch of the aqueous medium generated in the papermaking or pulping process. Can be done.

Step e): Contact of aqueous medium with hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate The pitch-containing aqueous medium provided in step a) according to step e) of the process of the invention is obtained in step d). The resulting hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate is contacted.

  In the process of the present invention, the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate can be contacted with the pitch-containing aqueous medium by any conventional feeding means known to those skilled in the art.

  The hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate can be added to the aqueous medium to be treated in any suitable form, for example in the form of granules or powder or in the form of a cake. Preferably, the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate is in powder form and / or fine grain form. In a preferred embodiment, the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate is in powder form prior to contact with the aqueous medium to be treated. Alternatively, hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate can be added to the aqueous medium to be purified as an aqueous suspension, for example in the form of a slurry.

  “Suspension” in the sense of the present invention comprises insoluble solids, ie hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate and water and optionally further additives. Suspensions usually contain large amounts of solids and are more viscous and generally denser than the liquid from which the suspension is formed. In the art, the general term “dispersion” specifically includes “suspension” as a particular type of dispersion.

  In one preferred method of the invention, the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate is suspended in water prior to contacting the aqueous medium to be treated. Preferably, such suspensions are from 1% to 80%, more preferably from 3% to 60%, even more preferably from 5% to 40%, based on the weight of the suspension. It has a content of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate in the range of% by weight.

  The hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate can be maintained in suspension, optionally further stabilized by a dispersant. Conventional dispersants known to those skilled in the art can be used. A preferred dispersant is polyacrylic acid.

  In the context of the present invention, it is also possible to provide a stationary phase in the form of a cake or layer comprising eg hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate, the aqueous medium passing through said stationary phase. In an alternative embodiment, the aqueous medium to be purified comprises hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate and optionally talc, where the liquid is by gravity and / or under vacuum and / or pressure. As it passes below, it passes through a permeable filter that can maintain impurities on the filter surface by size exclusion. This process is called “surface filtration”.

  In another preferred technique known as deep filtration, a filter aid that includes several meandering paths of varying diameters and configurations can introduce impurities into the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate present in the path. Impurities are retained by adsorbing molecular and / or electrical forces, and / or if the impurity particles are too large to pass through the total filter thickness, the impurity particles are retained by size exclusion.

  Preferably, the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate is suspended in a pitch-containing aqueous medium, for example by stirring means. The amount of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate varies with the type of pitch or pitch species adsorbed. Preferably, an amount of 0.05 to 25% by weight, more preferably 0.25 to 10% by weight, most preferably 0.5 to 2% by weight, based on the weight of the oven (100 ° C.) dry fiber. Added. Alternatively, the amount of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate used in the aqueous medium treatment is from 0.05 to 20% by weight, more preferably based on the total weight of the aqueous medium being treated. 0.5 to 10% by weight, still more preferably 0.1 to 5% by weight.

  In a preferred embodiment, the pH of the pitch-containing aqueous medium is greater than 6.0, more preferably greater than 6.5, even more preferably before the addition of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate. The value is adjusted to a value exceeding 7.0.

  In a preferred embodiment, talc is added to the pitch-containing aqueous medium in addition to the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate.

  Talc useful in the present invention can be any commercially available talc, such as Sotocamo (Finland), Three Springs (Australia), Haicheng (China), Alps (Germany), Florence (Italy), Tyrol (Austria), Shetland (Scotland), Transvaal (South Africa), Appalachian Mountains, California, Vermont and Texas (USA).

  Depending on the origin of the crude talc, the talc may contain multiple impurities such as chlorite, dolomite and magnesite, amphibole, biotite, olivine, pyroxene, quartz and serpentine.

  Preferred for use in the present invention is talc having a net talc content of greater than 90%, such as greater than 95% or greater than 97% and greater than 100% by weight.

The talc particles used in the present invention are 0.1 to 50 μm, for example 0.2 to 40 μm, preferably 0.3 to 30 μm, more preferably 0.4 to 20 μm, especially 0, measured according to the sedimentation method. It may have a weight median particle size d ₅₀ in the range of 5 to 10 μm, for example 1, 4 or 7 μm.

The specific surface area of talc, measured using nitrogen and BET, is between 3 and 100 m ² / g, preferably between 7 m ² / g and 80 m ² / g, more preferably between 9 m ² / g and 60 m ^2. / G, for example 51 m ² / g, especially between 10 and 50 m ² / g.

  Talc can be used in powder form. As an alternative, the talc can optionally be further stabilized by a dispersant and maintained in suspension. Conventional dispersants known to those skilled in the art can be used. The dispersant can be anionic or cationic.

  Preferably, the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate and talc are preferably mixed in powder form prior to contact with the pitch-containing aqueous medium to be treated. Blending can be done by any conventional means known to those skilled in the art.

  Alternatively, hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate and talc can be added to the pitch-containing aqueous medium in separate steps.

  Preferably, talc is suspended in the pitch-containing aqueous medium together with hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate, for example by stirring means. The amount of talc varies depending on the type of pitch or contaminant species adsorbed. Preferably, an amount of 0.05 to 25% by weight, more preferably 0.25 to 10% by weight, most preferably 0.5 to 2% by weight, based on the weight of the oven (100 ° C.) dry fiber. Added. Alternatively, the amount of talc used in the aqueous medium treatment is from 0.05 to 20% by weight, more preferably from 0.5 to 10% by weight, even more preferred, based on the total weight of the pitch-containing aqueous medium being treated. Is from 0.1 to 5% by weight.

  After adsorption is complete, the complex of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate, pitch and optionally talc is separated from the aqueous medium by conventional separation means known to those skilled in the art, such as sedimentation and filtration. Can be done.

  The aqueous medium obtained in step e) of the process is contained in the corresponding aqueous medium obtained by the same method, but without contacting the aqueous medium with hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate. The pitch is contained in an amount smaller than the amount of pitch. In a preferred embodiment, the aqueous medium obtained in step e) of the method is the corresponding aqueous solution obtained by the same method, but without contacting the aqueous medium with hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate. The colloidal pitch is contained in an amount smaller than the amount of pitch contained in the medium.

  Preferably, the aqueous medium obtained in step e) is reduced by at least 20% by weight, more preferably at least 50% by weight and most preferably at least 75% by weight over the pitch-containing aqueous medium provided in step a). Contains an amount of pitch.

  A further aspect of the present invention provides a composite material comprising hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate, pitch and optionally talc. When discussing method steps a), b), c), d) and e) with respect to the definition of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate, pitch, talc and their preferred embodiments, Reference is made to the description provided in.

  The hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate of the present invention has been shown to readily adsorb pitch species in a papermaking environment. In particular, the aqueous medium obtained by the process according to the invention is characterized in that it contains a considerably reduced amount of pitch or pitch species, for example colloidal pitch. Paper made from these aqueous media is characterized by fewer spots produced in the final product. Another advantage is that the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate reduces the tendency for deposits to form in papermaking equipment.

  In view of the very good results of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate in the reduction of pitch in aqueous media generated in papermaking or pulping processes as defined above, a further aspect of the invention Is the use of hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate in an aqueous medium that reduces the amount of pitch in the aqueous medium. According to another aspect of the present invention, an aliphatic carboxylic acid having a specific surface area between 10% and 19% of ground and / or precipitated calcium carbonate having between 5 and 24 carbon atoms and said aliphatic carboxylic acid Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate is provided, characterized in that it is covered by a coating consisting of an acid reaction product. With respect to the hydrophobized ground calcium carbonate and / or precipitated calcium carbonate and their preferred embodiments, reference is made to the description provided above when discussing method steps b), c), d) and e).

  The following figures, examples and tests illustrate the invention, but the invention is not limited to the illustrated embodiments. The examples below demonstrate the effectiveness of hydrophobized ground calcium carbonate and / or precipitated calcium carbonate to reduce the pitch in aqueous media generated in the papermaking or pulping process according to the present invention.

The normalized turbidity after mineral treatment of the TMP filtrate is shown. 100% corresponds to 349 NTU. Figure 2 shows the normalized chemical oxygen demand (COD) after mineral treatment of the TMP filtrate. 100% corresponds to 3644 mg O ₂ / dm ³ . The thermogravimetric analysis of the mineral after adsorption is shown. The weight loss rate is recorded between 200 and 1000 ° C. and corrected by the weight loss of the corresponding mineral powder. The normalized chemical oxygen demand (COD) value, gravimetric measurement and turbidity of the TMP filtrate after an adsorption experiment using mineral powder are shown relative to the surface coverage of the mineral powder with stearic acid. The thermogravimetric analysis of the mineral phase after an adsorption experiment is shown with respect to the surface coverage of the mineral powder with stearic acid. The weight loss of the starting mineral powder (before addition to the TMP filtrate) is drawn (net loss). A high surface area (HSA) talc samples including a hydrophobic mineral powder tested, along with a range of stearic acid coverage X _SA of the mineral powder. The larger the area on the right side of the line, the greater the hydrophobicity. The shaded area reflects the case of talc. Figure 5 shows adsorption isotherms based on turbidity data for untreated OMC-1, treated (15% surface coverage) ground calcium carbonate (GCC) and HSA-talc. The petroleum ether extract content of the TMP filtrate 4 before and after adsorption is shown. The extracts are divided into groups: fatty acids, resin acids, lignans, sterols, steryl esters, triglycerides and unknown fractions. The relative composition of the extract group in the TMP filtrate before and after adsorption is shown. 2 shows carbohydrate acid solubility and acid insoluble content in the TMP filtrate before and after adsorption.

Materials and methods
1. Four independent tests are provided using unbleached TMP consisting of 70% spruce with pitch-containing pulp , the rest consisting of fir and a small amount of pine. These TMP samples were collected at a Swiss paper mill. The factory uses 100% fresh water in the factory's TMP plant. Prior to the bleaching step, fresh wet pulp was obtained at a temperature of 90 ° C. with a screen “pass” indication. The TMP was allowed to cool overnight to room temperature (rt). TMP was filtered through a filter (filter paper, circular 602EH) with a pore size of 2 μm. The filtrate was checked by an optical microscope (Olympus AX-70) for fibers and fibrils. Adsorption experiments were performed immediately after filtration. The pH of the filtrate was usually between 6.0 and 7.0. The pH was adjusted from 7.0 to 7.5 with 0.1M sodium hydroxide.

  In order to quantify the colloidal stability of the wood resin droplets, pH titration of electrophoretic mobility was performed. This was done on a Malvern Zetasizer using 0.1M hydrochloric acid solution and 0.1M sodium hydroxide solution. In addition, the total electrochemical charge was measured using a flow current detector (SCD) made by Mutek (PDC-03), and the TMP filtrate was converted to 0.0025 M poly-DADMAC [poly- (allyldimethyl-ammonium chloride). Determined by titration. In addition, the ion content was quantified by ion chromatography on a Dionex DX 120 ion chromatograph.

After pH adjustment, the TMP filtrate was distributed into glass bottles each containing 200 cm ³ of TMP filtrate. The desired amount and type of mineral was added as either a powder or a dispersion in water. Mineral usage in the majority of cases is 10 g / dm ^3, in the case of isothermal lines, mineral consumption varied between 2.5 and 50.0 g / dm ^3. The same amount of water (usually 18 cm ³ ) was added to all samples in one test row. The bottle was equipped with a magnetic stir bar, and the hermetic lid was closed and stirred with a magnetic stirrer for 2 hours. After 2 hours, the magnetic stir bar was removed and the experimental mixture was centrifuged at 2600 g for 15 minutes (Jouan C 312 from IG Instruments). Two phases: a liquid upper phase and a precipitated mineral-containing lower phase were collected. No sediment was seen by centrifugation of the untreated TMP filtrate. However, due to sedimentation of the pure mineral dispersion, in some cases, mineral particles trapped with bubbles were seen.

The turbidity of the upper liquid phase was analyzed with a Nova Sina 155 model NTM-S turbidity probe. The particle size was measured by photon correlation spectroscopy on a Malvern Zetasizer NS without any further processing or dilution. Chemical oxygen demand (COD) was measured with a LASA 1 / Plus cuvette, using a Range CSB LCK 014, covering a range of 1000 to 10000 mg / dm ³ . A liquid phase of 100 cm ³ was dried in an aluminum beaker at 90 ° C. for 12 hours, and the residue was weighed to obtain a gravimetric residue result.

  The properties of the TMP samples are summarized in Table 1 below. The range shown is based on the standard deviation of three independent experiments.

In one test setup, the liquid upper phase was also analyzed for wood extract content and carbohydrate content. Wood extract content was determined by extracting the TMP filtrate with petroleum (Saltsman et al., 1959, Estimate of tall oil in sulfate black liquor, Tappi, 42 (11), 873). GC-FID analysis for group determination of wood extracts was performed according to the method of Orsa and Holmbom (Orsa et al., 1994, A convenient method for the affairs of peroxidatives in perperm. Pap.Sci., 20 (12), 361). The sample was hydrolyzed in an autoclave with 121 ° C. sulfuric acid according to SCAN-CM 71:09. The dissolved monosaccharide was quantified using an ion chromatograph connected to a pulse current detector (IC-PAD). The acid insoluble residue was determined gravimetrically and the acid soluble residue (lignin) was measured by UV spectroscopy at 205 nm and quantified using an extinction coefficient of 110 dm ³ / (gcm).

  The lower phase containing precipitated minerals was analyzed by thermogravimetric analysis (TGA) on a METTLER TOLEDO TGA / STDA 851e. The sample was heated from 20 to 1000 ° C. at a heating rate of 20 ° C./min. The weight loss was recorded between 20 and 1000 ° C.

2. Minerals In this study, various mineral powders were tested. On the one hand, the talc grade from Finland was used as a reference. One is the commercial talc by Mondo Minerals, Fintalc P05, and the other talc grade is obtained by subsequent grinding and delamination of Fintalc P05 to obtain fineness, high aspect ratio and specific surface area improvement. can get. Fin talc P05 is called LSA (low surface area) talc and delamination quality is called high surface area (HSA-talc) talc. The specific surface areas and particle sizes of various mineral powders are reported in Table 2 below.

Specific surface area, particle size (d ₅₀ ) and electrophoretic mobility were determined in 0.01 M NaCl solution as the medium for the mineral suspension investigated.

  On the other hand, various ground calcium carbonate grades were tested. One is marketed as Omyacarb 10 (OMC-10), the other as Omiyacarb 1 (OMC-1), and the third quality is OMC-1 and OMC, both low surface area ground calcium carbonate Made from OMC-1 by chemical-free grinding to obtain a high surface area ground calcium carbonate (HSA-GCC) compared to -10. Ground calcium carbonate samples were supplied by Omiya and were from Avenza, Italy.

  Specific surface area was measured by nitrogen adsorption on a Micrometric Tristar based on the BET adsorption model according to ISO 9277 using nitrogen after adjusting the sample by heating at 250 ° C. for a period of 30 minutes. Prior to such measurements, the samples were filtered through a Buchner funnel, rinsed with deionized water, and dried in an oven at 90-100 ° C. overnight. Subsequently, the dried cake was completely pulverized in a mortar, and the resulting powder was placed in a 130 ° C. moisture meter until a constant weight was reached.

The weight median sphere equivalent hydrodynamic particle size (d ₅₀ ) was measured by Micrometrics Cedigraph 5120 under sedimentation. The sedimentation method is an analysis of sedimentation behavior in a gravimetric field. Methods and apparatus are known to those skilled in the art and are commonly used to determine filler and pigment particle sizes. The measurement is performed in a 0.1 wt% Na ₄ P ₂ O ₇ aqueous solution. Samples were dispersed using a high speed stirrer and ultrasound.

3. Stearic acid treated stearic acid was a high purity grade manufactured by Sigma-Aldrich. The GCC powder was charged into an MTI mixer (model M3 / 1.5) heated to 80 ° C. The powder was stirred at 3000 rpm for a period of 2.5 minutes. Stearic acid was added to the preheated powder. In order to obtain a product with a given coverage, the amount of stearic acid was calculated according to equation 1 defined above. The formulation was again stirred at 3000 rpm for 2.5 minutes. The mixer was opened and the powder was manually mixed to disperse uniformly in the mixer, closed again, and stirred at 3000 rpm for an additional 2.5 minutes of mixing time. The mixer temperature was maintained at 80 ° C. throughout the procedure.

To calculate the surface coverage, but using Equation 2, wherein, m _SA is stearic acid that must be added to handle the calcite 1g surface coverage chi _SA by stearic acid (SA) Is the mass. It has a specific surface area sigma _M minerals obtained by nitrogen adsorption, of stearic acid molecule weight _{M WSA,} it is Avogadro constant _{N A} and 0.26 nm ^2, with a surface area _{A SA} that has been coated with one molecule of stearic acid calculate.

4). A mixture of semi-quantitative wet test water and ethanol was used at 100: 0, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, 10:90. And a volume ratio of 0: 100. Each 50 cm ³ of these mixtures was placed in a 100 cm ³ beaker. About 0.5 to 1.0 g of the powder in question was carefully placed on the liquid. Wetting behavior was quantified by the time required to wet the powder according to the following judgment:
0 → immediate wetting of powder (sink within 30 seconds)
0.25 → within 5 minutes after the whole powder is wet 0.5 → more than 50% of the powder is wet after 5 minutes 0.75 → less than 25% of the powder is wet after 5 minutes Not wet within

B. result
1. Surface coverage and pitch adsorption capacity with stearic acid To determine the degree of surface coverage with stearic acid and the pitch adsorption capacity of the surface coating with stearic acid, a plurality of samples, namely OMC-10, OMC-1 and HSA-GCC Were treated with 30% and 60% stearic acid (based on surface area) to test the extent of stearic acid treatment and the effect of surface area. For comparison of reasons, untreated ground calcium carbonate and LSA talc were also tested.

The TMP filtrate used was Sample 1 (collected in November 2009) and analyzed as described above in Table 1. The electrophoretic mobility of the particles in TMP filtrate 1 was found to be −0.5 × 10 ⁻⁸ m ² / (Vs). The EM remained constant within the relevant pH range of 7-8.

  It was found that the ground calcium carbonate product coated with 60% area by stearic acid could not be wetted by the TMP filtrate resulting in foam and undefined phase after centrifugation. For this reason, no results were obtained for these products. Even with the 30% surface treated sample, wetting was a problem. Interestingly, wetting improved during the experiment, which suggests adsorption of surface active compounds from the TMP filtrate.

  The turbidity of the TMP filtrate was clearly reduced as a result of mineral addition (see FIG. 1). The reduction of the specific surface area (SSA) further improved the removal efficiency of the colloidal material. In the case of 30% surface coated ground calcium carbonate, turbidity was reduced to 77% of the original 349 NTU by OMC-10, 41% by OMC-1 and 21% by HSA-GCC. Treatment with stearic acid increased the efficiency of colloidal pitch adsorption. Both the surface treated and surface untreated ground calcium carbonate products still reduced turbidity more efficiently than LSA talc, which only reduced 50%. However, the observed efficiency can also be caused by the agglomeration process of the wood resin droplets. The particle size before and after adsorption in the liquid phase was slightly reduced.

  Since particle size analysis in the liquid phase did not include aggregates that settled during centrifugation, it is also important to consider other analyzes such as COD (see FIG. 2) or TGA (see FIG. 3). . The COD analysis showed a slightly different trend. On the other hand, no significantly different values were shown for OMC-10 values and for both fatty acid-treated HSA-GCC and untreated HSA-GCC. The only difference was observed with OMC-1 which, conversely, was untreated ground calcium carbonate appeared to be more efficient for turbidity. A possible explanation for these opposite observations can be that different species are adsorbed on the treated and untreated ground calcium carbonate powder. In the case of the treated ground calcium carbonate powder, the adsorbable compound rather contributes to turbidity and thus is colloidal in nature, and in the case of untreated ground calcium carbonate powder, the adsorbable species is rather soluble in nature. , Preferentially contribute to turbidity rather than COD. Moreover, talc powder shows almost the same efficiency as pulverized calcium carbonate powder. Turbidity analysis was again confirmed by analysis of the mineral phase after the adsorption experiment. The amount of adsorption on the mineral surface increased with the specific surface area. Partially hydrophobized ground calcium carbonate adsorbed slightly more material than native ground calcium carbonate, ie non-hydrophobized and non-surface treated ground calcium carbonate. Both hydrophobized and unmodified ground calcium carbonate adsorbed more material than talc.

  Furthermore, it was found that treatment with ground calcium carbonate clearly increased the pH from 7.0 to 7.8. The conductivity also increased from 926 μS / cm to 980 μS / cm. Of great importance in the paper mill water circuit is the calcium ion concentration. Calcium ions can be one of the main triggers for pitch aggregation. The concentration increased from 1.45 mM to 1.90 mM. The addition of talc did not affect the calcium ion concentration.

  Thus, treatment of the ground calcium carbonate surface with stearic acid is beneficial for pitch adsorption, but excessive surface treatment with stearic acid can cause wetting problems.

2. Degree of surface coverage with stearic acid An attempt was made to optimize the amount of stearic acid surface treatment with a surface coverage of _SA from 0 to 30%. OMC-1 was used for this optimization. Again, TMP filtrate 1 was used. The electrophoretic mobility (EM) of the original TMP filtrate is −0.8 × 10 ⁻⁸ m ² / (Vs), and the dramatic change in EM is in the relevant pH range of this study (7-8). Not observed.

  Already during the test, it was observed that the higher the surface coverage with stearic acid, the more difficult it was to soak the powder in the TMP filtrate, resulting in the formation of a foam layer. This undefined phase clearly affected turbidity measurements (see FIG. 4). The optimum conditions for turbidity reduction were obtained at a surface coverage of 15%. From the COD and gravimetric measurements, it was not possible to distinguish between the different degrees of processing. Thermogravimetry (see FIG. 5) also showed that the optimum usage was about 15%. Finally, a semi-quantitative hydrophobicity test (see FIG. 6) showed that a sample with a surface coverage of about 15% had a hydrophobicity comparable to talc.

3. Adsorption Isotherm For further study, an OMC-1 product with a specific surface area of 3.9 m ² / g and a surface coverage with stearic acid of about 15% was used.

In order to quantify the effect of stearic acid treatment adsorption, isotherms of untreated OMC-1 and OMC-1 having a surface coverage of about 15% with stearic acid were recorded. For comparison, high surface area talc (HSA talc) was also included. The isotherm was recorded at 24 ° C. For this work, TMP filtrate 3 was used which gave an electrophoretic mobility of particles of −0.8 × 10 ⁻⁸ m ² / (Vs). Within the relevant pH range of 7-8, the EM changed very little. The analysis of the TMP filtrate before the adsorption experiment is shown in Table 1 above.

The adsorption isotherm shows the amount of addition to the mineral phase that has reached equilibrium (Γ _eq ^turbo ) ^versus the equilibrium concentration in the liquid phase determined by turbidity (c _eq ^turbo ), ie in this case the turbidity is A parameter containing information on the equilibrium concentration of the colloid. The amount of seeds that generate “turbidity” for minerals is calculated by ^subtracting the equilibrium concentration (c _eq ^turb ) of the liquid phase from the initial turbidity (c ₀ ^turb ) before adsorption using Equation 3 below. Calculated by

The Langmuir adsorption isotherm is shown by Equation 4 below. Γ is the amount of adsorbate added to the adsorbent (mineral) in an equilibrium state. c _eq is the bulk concentration of adsorbate in equilibrium. Due to the Langmuir constant (K _L ), the untreated ground calcium carbonate powder has a higher affinity (0.025 (NTU) ⁻¹ ) for colloidal materials than partially hydrophobized (0.013 (NTU) ⁻¹ ). ) (See Table 3). HSA- talc grade, showed the lowest affinity (0.007 ^{(NTU) -1)} with the lowest _{K L.} The maximum addition amount (Γ _max ) increases from untreated (25 NTU / g) to treated (37 NTU / g) OMC ^{−1 as} can be summarized from Table 3 below and FIG.

  The adsorption isotherm parameters are based on non-linear least squares (NLLS) fitting to the Langmuir equation (Equation 4) performed by TableCurve® 2D.

The difference between the fitted parameters KL and Γ _max is significant. As a result of the high specific surface area of HSA talc (45 m ² / g) versus the specific surface area of OMC-1 having only about 4 m ² / g, the maximum amount of colloidal particles added to talc (212 NTU / g) is Proportionally more.

4). Chemical analysis TMP filtrate 4 with electrophoretic mobility of particles of −0.6 × 10 ⁻⁸ m ² / (Vs) at the original pH 7.2 was collected for chemical analysis and aggregation tests. Again, EM was stable in the relevant pH range of 7-8. The properties of TMP filtrate 4 are listed in Table 1 above.

Different amounts of mineral were added to the TMP filtrate to cover the relevant area of the adsorption isotherm. In the case of HSA-talc, the amount of talc used is 0.4 g / dm ³ so as to correspond to the region where the dissolved and colloidal substance is excessive, and 4 g / dm ³ so as to correspond to the region where the talc surface is excessively available. Provided talc usage. Since the specific surface area of the ground calcium carbonate powder was much smaller (see Table 2 above), the mineral loading was increased from 8 to 40 g / dm ³ .

The petroleum ether extract content of TMP filtrate 4 was 142 mg / dm ³ as outlined in Table 4 below and FIG. Table 4 further summarizes the carbohydrate content, acid solubility (lignin) content, and acid insoluble content of the TMP filtrate 4 as described further below.

The petroleum ether extract content of TMP filtrate 4 is approximately 4% of the total material in the TMP filtrate. The main constituent of the extract is triglycerides (44%, triacylglycerides), followed by resin acids (23%) and steryl esters (18%). Free fatty acids (6%), lignans (2%) and sterols (2%) were rather insignificant. The remaining 5% is of unknown origin. As can be inferred from FIG. 5, the extract content decreases to 12 mg / dm ^{3 with} the addition of 0.4 g / dm ³ HSA-talc and the extract content of 32 mg / dm ³ with the addition of 4 g / dm ³ Occurred. The ratio of the extract group was not affected in either case (see FIG. 9). The use amount of 8g ^/ dm 3 OMC-1, extract content up to 107 mg / dm ^3, and decreased respectively from 40 g / dm ³ to 28 mg / dm ^3. The ratio of the extract group was not affected by low mineral usage, but was strongly influenced by high mineral usage. A similar situation was observed with hydrophobized OMC-1 (OMC-1 “treatment”). The lower mineral usage resulted in an extract residue of 73 mg / dm ³ and the higher mineral usage yielded 23 mg / dm ³ respectively.

In addition, the water soluble portion of the TMP filtrate was also analyzed. This analysis is divided into three fractions: i) carbohydrates, ii) acid solubles (lignin) and iii) acid insolubles (wood resin, salt, etc.). In this respect, it is utilized that only lignin in the acid-soluble fraction has an absorption maximum at 280 nm by UV spectroscopy. Therefore, by measuring the UV spectrum, the soluble lignin contained in the acid-soluble fraction can be determined. Original TMP filtrate 4 contains carbohydrates 1052mg / dm ^3, acid-soluble product of 527 mg / dm ³ (the lignin) and the acid-insoluble material in 403 mg / dm ³ (see FIG. 10, Table 4). The carbohydrate content during talc treatment decreased only slightly at low talc usage (1034 mg / dm ³ ), but at high talc usage (696 mg / dm ³ ), the carbohydrate content decreased significantly. Untreated OMC-1 adsorbed only a small percentage of carbohydrates. 1024 mg / dm ³ was measured at a low usage amount, and 952 mg / dm ³ was measured at a high OMC-1 usage amount. Hydrophobized OMC-1 adsorbed a very small amount. The carbohydrate content was approximately 980 mg / dm ³ for both mineral usages. In the case of the acid lysate (lignin) fraction, the decrease after mineral treatment was less than 3%, except for 4 g / dm ³ of HSA-talc. In this case, the residual lignin content was 396 mg / dm ³ . The acid-insoluble fraction eventually changed proportionally with the decrease in extract.

  As a result of the alkaline nature of the mineral powder, the pH of the sample increased. The lower the mineral usage, the pH is between 7.3 and 7.6, and the higher usage is 7.7 to 7.8.

  The calculated ratio between dissolved and colloidal material in the TMP filtrate 4 before and after adsorption is shown in Table 5 below.

  The ratio of the amount of extract to the amount of carbohydrate plus acid insoluble lignin is calculated as in Equation 2. In Table 5, when the amount of talc used is high (excess talc surface), the ratio of dissolved material to colloidal material clearly moves towards the dissolved fraction (4.4). A possible explanation could be that pitch droplets adsorb with the stabilized carbohydrate layer (low mineral usage) of the pitch droplets, thus producing a constant ratio. After removing most of the colloidal fraction (high mineral usage), talc also adsorbs dissolved substances such as carbohydrates, lignin and dissolved wood resin components (resin acids, etc.), whereas ground calcium carbonate dissolves Does not adsorb substances from the rate. It was also shown that these adsorption priorities differed by colloidal adsorption isotherms in the form of Langmuir constant KL. For the colloidal fraction, the lowest affinity was shown by talc and the highest affinity was shown by untreated GCC. Interestingly, the affinity of hydrophobized GCC was intermediate.

Another observation was that a significant amount of resin acid was found in the aqueous phase when the amount of ground calcium carbonate was high. A possible explanation could be that the resin acid was dissolved during the adsorption experiment. It is known that about 20-30 mg / dm ³ dissolves in the pH range of 7-8. When the amount of mineral used was large, the pH after the adsorption experiment was measured as 7.8. Since the pH before the extraction procedure has been acidified, the resin acid becomes insoluble again and is measured as part of the extract.

  For this reason, hydrophobized ground calcium carbonate is preferred to effectively reduce colloidal material, i.e. pitch, from the sample, whereas talc is preferred to recover the dissolved carbohydrate rate.

  As a result, especially hydrophobized ground calcium carbonate has been shown to immediately adsorb pitch species in the papermaking environment. A typical pitch control talc does not appear to have enough surface area to process all the components that are believed to be contained in the pulp. Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate or their combination with talc offers the possibility of synergistic aqueous treatment for TMP wood pitch.

Claims (30)

A method for reducing the pitch in an aqueous medium generated in a papermaking or pulping process, comprising:
a) providing an aqueous medium comprising a pitch generated in a papermaking or pulping process;
b) providing ground calcium carbonate and / or precipitated calcium carbonate;
c) providing a hydrophobizing agent selected from aliphatic carboxylic acids having between 5 and 24 carbon atoms;
d) contacting the ground calcium carbonate and / or the precipitated calcium carbonate of step b) with the hydrophobizing agent of step c) to obtain hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate; e) contacting the aqueous medium provided in step a) with the hydrophobized ground calcium carbonate and / or the hydrophobized precipitated calcium carbonate obtained in step d).   2. A method according to claim 1, wherein the ground calcium carbonate (GCC) source is selected from marble, chalk, calcite, dolomite, limestone and mixtures thereof, and / or precipitated calcium carbonate (PCC) is aragonite, vaterite. And one or more of calcite mineral crystal forms.   3. A method according to claim 1 or 2, wherein the ground calcium carbonate and / or the precipitated calcium carbonate is in the form of a powder or slurry. The method according to claim 1 or 2, ground calcium carbonate particles and / or precipitated calcium carbonate particles were measured according to the sedimentation method, with a heavy weight median particle size d ₅₀ value of 50μm from 0.1, method . 3. A method according to claim 1 or 2 , wherein the ground calcium carbonate particles and / or precipitated calcium carbonate particles are measured using nitrogen and the BET method at a ratio of 0.5 m ² / g to 25 m ² / g . A method having a surface area. The method according to claim 1 or 2 , wherein the hydrophobizing agent is pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid. , palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, arachidic acid, heneicosylic acid, behenic acid, Toriikoshiru acid is selected from the group consisting of lignoceric acid and mixtures thereof, methods. 3. A method according to claim 1 or 2 , wherein the hydrophobizing agent comprises a mixture of two aliphatic carboxylic acids having between 5 and 24 carbon atoms, and one of the aliphatic carboxylic acids is stearic acid. Is that way.   8. The method of claim 7, wherein one aliphatic carboxylic acid is stearic acid and the other is selected from the group consisting of octanoic acid, myristic acid, palmitic acid, arachidic acid, behenic acid and lignoceric acid. ,Method. 3. A method according to claim 1 or 2 , wherein step d) is performed by mixing ground calcium carbonate and / or precipitated calcium carbonate with a hydrophobizing agent. 3. A method according to claim 1 or 2 , wherein the ground calcium carbonate and / or the precipitated calcium carbonate of step b) and the hydrophobizing agent of step c) are provided in a dry state or in a solvent. d) is performed. 3. A method according to claim 1 or 2 , wherein step d) is carried out, wherein the ground calcium carbonate and / or the precipitated calcium carbonate of step b) or the hydrophobizing agent of step c) are provided in a solvent. ,Method. 3. A method according to claim 1 or 2 , wherein step d) is carried out at an elevated temperature so that the hydrophobizing agent is in a liquid or molten state. The method according to claim 12, wherein step d) is performed at a temperature of at least 50 ° C. The method according to claim 1 or 2, 20% less than the specific surface area of the hydrophobized ground calcium and / or the hydrophobized precipitated calcium carbonate obtained in step d) is, the hydrophobizing agent and the The method is covered by a coating comprising a reaction product of a hydrophobizing agent. 15. The method according to claim 14, wherein between 10% and 19% of the specific surface area of the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate obtained in step d) comprises the hydrophobizing agent and The method is covered by a coating comprising a reaction product of the hydrophobizing agent. The method according to claim 1 or 2, the aqueous medium to be processed, on the basis of the total weight of the aqueous medium, coarse hydrated ground calcium carbonate from 0.05 to 20% by weight and / or hydrophobic precipitated A method wherein the calcium carbonate is contacted. 3. A method according to claim 1 or 2 , wherein the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate obtained in step d) is used in powder form and / or in the form of fine granules or slurry. The way it is. The method according to claim 1 or 2, pH of the pitch containing aqueous medium, prior to the addition of hydrophobized ground calcium and / or hydrophobized precipitated calcium carbonate is adjusted to exceeds the 6 values, the method . The method of claim 18, wherein the pH of the pitch-containing aqueous medium is adjusted to a value greater than 6.5. The method according to claim 1 or 2, the pitch containing aqueous medium, Ru is used in the papermaking process, mechanical pulp containing crushed wood, TMP (thermomechanical pulp) or chemithermomechanical pulp (CTMP), as well as, A method selected from the group comprising chemical or recycled pulp, including kraft pulp or sulfate pulp. Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate, wherein between 10% and 19% of the specific surface area of said ground calcium carbonate and / or said precipitated calcium carbonate is between 5 and 24 carbon atoms Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate, which is covered by a coating consisting of an aliphatic carboxylic acid having a reaction product of the aliphatic carboxylic acid. Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate, wherein between 10% and 19% of the specific surface area of said ground calcium carbonate and / or said precipitated calcium carbonate is a reaction product of stearic acid and stearic acid Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate, which is covered by a coating consisting of 23. Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate according to claim 21 or 22 , wherein between 13% and 17% of the specific surface area of said ground calcium carbonate and / or said precipitated calcium carbonate is 5 aliphatic be overturned are in that, hydrophobized ground calcium and / or hydrophobized precipitated calcium carbonate by the coating comprising a reaction product of a carboxylic acid and the aliphatic carboxylic acids having 24 carbon atoms of between. 24. Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate according to claim 23, wherein the coating comprising the aliphatic carboxylic acid and the reaction product of the aliphatic carboxylic acid is a reaction of stearic acid and stearic acid. Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate, which is a coating consisting of the product. 23. Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate according to claim 21 or 22 , wherein the ground calcium carbonate (GCC) source comprises marble, chalk, calcite, dolomite, limestone and mixtures thereof. And / or hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate, wherein the precipitated calcium carbonate (PCC) is selected from one or more of aragonite, vaterite and calcite mineral crystal forms. 23. Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate according to claim 21 or 22 , wherein the ground calcium carbonate particles and / or precipitated calcium carbonate particles are 0.1 to 50 μm, measured according to the sedimentation method . having heavy weight median particle size d ₅₀ values, hydrophobized ground calcium and / or hydrophobized precipitated calcium carbonate. 23. Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate according to claim 21 or 22 , wherein the ground calcium carbonate particles and / or precipitated calcium carbonate particles are measured using nitrogen and the BET method. Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate having a specific surface area of 0.5 m ² / g to 25 m ² / g. 23. Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate according to claim 21 or 22 , wherein the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate is in the form of powder and / or fine particles or slurry. Hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate in the form of Use of the hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate according to claim 21 or 22 , wherein the amount of pitch in the aqueous medium generated in the papermaking or pulping process is reduced. 23. A composite material comprising hydrophobized ground calcium carbonate and / or hydrophobized precipitated calcium carbonate and pitch according to claim 21 or 22 .

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